Campbell-scientific CR9000X Measurement and Control System Manual de usuario descargar pdf (Pagina 179)

Section 5. Program Declarations

encountering the EndFunction command, the Function will

return NAN.

Function Example

'In this example, Function Secant calculates the secant of an angle. Note

'that the Angle variable's value, in the main Scan, would not be modified

'by the Function call.

AngleDegrees

Public Angle, Var, Secant, X, Y

Function Secant(F_Angle as Float) as Float

Dim F_Angle

Secant = 1/Cos(F_Angle)

EndFunction

BeginProg

X=1 : Y = 1 ' Initialise X, and Y so the angle is 45 degrees

Scan(1,Sec,3,0)

Angle = ATN2(X,Y)

Var = Secant(Angle)

NextScan

EndProg

PUBLIC

Like the Dim statement, the Public statement is used to declare variables and

variable arrays, and allocate storage space for these variables.

The difference is

that variables declared using the Public statement can be monitored at the

measurement scan rate using the various CSI software packages through the Public

Table.

Syntax

Public VarName (size subscripts) Or

Public VarName (size subscripts) As Type Or

Public VarName (size subscripts) As Type = {3,6,2, . , , ,5}[initialise values]

Remarks

In CRBasic, ALL variables MUST be declared. Variables are typically declared

at the beginning of the program and the default value is initialized to a value of 0

unless otherwise declared.

A Public statement can be used for each variable declared, or multiple

variables can be defined on one line with one Public statement. If the latter is

done, the variables should be separated by a comma (e.g., "Public Scratch1,

Scratch2, Test" declares three variables). A variable array is created by

following the variable name with the number of elements enclosed in

parenthesis (e.g., Public Temp(3) creates Temp(1), Temp(2), and Temp(3)).

Two- and three-dimensional arrays can also be defined. A declaration of Dim

Temp(3,3,3) would create 29 variables: Temp(1,1,1), Temp(1,1,2),

Temp(1,1,3), Temp(1,2,1), Temp(1,2,2) … Temp(3,3,3). In the program, the

array can be referenced using the multi-dimensional form, or using an index

into the array.

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